Interconnected pivoted latch means for die-heads



April 23, 1963 R. M. STRICKLAND 3,

INTERCONNECTED PIVOTED LATCH MEANS FOR DIE-HEADS Filed Sept. 12, 1961 2Sheets-Sheet 1 44 4 IO 46 30) 28 2. i 15 2 4 2 50 90 '9 1' 1 f as I2INVENTOR Royce M. STR/C/(L AND A11: Arron/a vs.

April 3, 1963 R. M. STRICKLAND INTERCONNECTED PIVOTED LATCH MEANS FORDIEHEADS Filed Sept. 12, 1961 2 Sheets-Sheet 2 INVENTOR RovcE M- S'TR/ckuwo 51's Arrozzwzys United States 'Patent 3,086,229 INTERCONNECTEDPIVOTED LATCH MEAN FOR DIE-HEADS Royce M. Strickland, New Haven, Conn,assignor to United-Greenfield Corporation, Chicago, 111., a corporationof Delaware Filed Sept. 12, 1961, Ser. No. 137,693 7 Claims. (Cl. -95)The present invention relates to thread-cutting die-he ads, and itrelates more particularly to latch means for locking the thread cuttingelements or chasers in a predetermined position.

It is common practice to provide die-heads with means for latching thechaser operating or closing member in a working position where thechasers are to be fixed for cutting the desired threads in a work-piece.Latch means may also be used to limit the movement of the operatingmember beyond the so-called chaser-retracted position on certain typesof die-heads where the chasers are positioned out of engagement with thework and, in other types of die-heads, in the chaser-clearance positionwhere the operating member is clear of the chasers so that they can beremoved and replaced. Upon the release of the chaser-operating member bydisengagement of such latch means, the 'chasers, which are spring-loadedaway from their working position will retract outwardly from oneposition to the next. An example of a die-head of the self-opening typein which such latch means are employed isshown in the patent toBreitenstein, 1,639,719. In the Breitenstein construction, as in mostself-opening dieheads two separate latch means are provided, one forlatching the operating member in working position and theother forlatching it in the chaser-retracted position. Upon release of theoperating member from its chaserretracted position, it move to itschaser-clearance position. However, in the so-called solid ornon-self-opening type of die-head, the chaser-operating member usuallyhas only two positions, a working position and a chaserclearanceposition. In addition, in most die-heads, whether of the self-opening orsolid type, the chasers may be adjusted for cutting threads of precisediameters.

In die-heads of either the self-opening or solid type with which thepresent invention is concerned, the chaseroperating member. consists ofa closing sleeve supported by a frame or skeleton for longitudinalmovement thereon. The chasers are mounted in radial tracks at the frontend of the skeleton and are engaged at their outer ends by a closingsleeve which, when moved forwardly, forces the chasers inwardly to theirworking positions and, when moved :rearwardly, permits them to moveoutwardly to their retracted positions. When the closing sleeve is movedsufiiciently far to the rear, it clears the outer ends of the chasers sothat they can be removed from their tracks and replaced when in need ofsharpening or when a different thread is required. p The primary objectof the present invention is to provide an improved stop-means forlatching the operating member in any one of the positions mentionedabove depending on the particular type of die-head involved. Anotherobject of the invention is to provide stop-means for the operatingmember which prevent it from being cocked out of line with the adjacentparts or from binding so that it does not move freely.

In general the invention resides in improved stop-means for theoperating member comprising two or more stoplevers, desirably equallyspaced about the longitudinal axis of the skeleton, each stop-leverbeing pivoted intermediate its ends for movement into and out oflatching position with respect to the operating member. The ends of thestop-levers are interconnected so that if one is moved out of latchingposition, all are pivoted out of latching position simultaneously.Resilient means, such as springs, urge the stop-levers into latchingposition.

In order that a clearer understanding of the invention may be obtained,one practical embodiment thereof is described hereinafter with referenceto the accompanying drawings showing application of the invention in adiehead of the solid or non-self-opening type.

In the drawings,

FIG. 1 is a central longitudinal vertical section through a typicaldie-head in which the invention may be employed;

FIG. 2 is a section taken on the line 22 of FIG. 1, but showing theadjusting ring rotated 45 in a clockwise direction from its position inFIG. 1;

FIG. 3 is a section taken on the line 3-3 of FIG. 1, but showing theadjusting ring in the position shown in FIG. 2;

FIG. 4 is a view similar to FIG. 3, but showing the stop-leversdepressed out of latching position;

FIG. 5 is a front end View partially broken away of the die-head shownin FIG. 1;

FIG. 6 is a detail sectional view taken on the line 66 of FIG. 5; and

FIG. 7 is a perspective View of the adjusting ring only.

The particular die-head illustrated by way of example in the drawingsincludes a main frame or skeleton, socalled, having a cylindricalhead-portion 1t and a central shank 12 extending rearwardly therefrom.The forward face of head-portion 10 is formed in this instance with fourradial slots 14 (FIGS. 5 and 6), in each of which is guided a chaserholder 16. Holders 16 carry individual thread-cutting dies or chasers 18for threading a workpiece (not shown). The chaser assembly of thepresent construction is similar to that shown in the patent toBreitenstein, 1,756,277, and need not, therefore,.be described in detailhere. It will be understood, of course, that other types of chasers maybe employed if desired. For example, the chasers may be mounted directlyin slots 14 instead of on holders 16. p

In the construction here illustrated, chaser holders 16 are retained inslots 14 by means of segmental plates 19, which are rigidly secured tothe forward face of the skeleton by screws 29. Each chaser holder 16 isurged outwardly toward its retracted position by a spring plungerassembly 22 (FIG. 6). In addition, each holder 16 is formed at its outerend with a sloping cam-surface 24, which is engaged by asimilarly slopedcam-surface 26 formed on the inner forward corner of a cup-shaped,chaser-operating sleeve 28. Sleeve 28 is mounted on the skeleton foraxial sliding movement thereon and bears along the inner sides of itsforwardly extending walls 30 on the periphery of head-portion it) of theskeleton. Sleeve 28 is provided at its rear end with an inwardlydisposed annular flange 32, the inner edge of which bears against theperiphery of a cylindrical adjusting ring 34 threadedly mounted on shank12 of the skeleton. It will be seen that axial movement of sleeve 28forwardly cams chasers 18 into working position, while rearward movementthereof permits the chasers to retract outwardly. A key 36 (FIG. 5),fitting a keyway 38 in the inner surface of wall 30 of sleeve 28,prevents rotation of sleeve 28 with respect to head-portion 10 of theskeleton.

In passing, it should be noted that in the particular die-headconstruction here shown, the walls 30 of operating sleeve 28.,arerelatively narrow longitudinally of the skeleton. While certainadvantages are attained by employing such a narrow operating sleeve,there is a tendency, nevertheless, due to the construction for thesleeve to tilt more easily when moved axially and therefore to bind orbecome jammed while the chasers are being moved int-o the desiredworking or operating position.

It is important therefore in moving the operating sleeve 28 forward toexert pressure symmetrically, i.e. on both sides, of the rear face ofthe sleeve in order to prevent it from binding. As will be brought outhereinafter, the present invention makes it practical to do this.

Operating sleeve 28 is urged in a rearward direction by a pair of springplungers 46 carried by the cylindrical head-portion 10 of the skeletonand disposed on diametrically opposite sides thereof. Plungers 4d areguided within bores 42 drilled in head-portion 19 parallel to thelongitudinal axis of shank 12. Each plunger 46 is provided with a socket44, within which is received one end of a coil spring 46 which urges theplunger rearwardly against flange 32 of operating sleeve 28. The forwardend of each spring 46 rests against the inner side of one of thesegmental plates 19 at the front face of the diehead. It will be notedthat each plunger is formed with a clearance cut 48 at its rear orsleeve-engaging end in order to avoid engagement with adjusting ring 34and to permit adequate rearward movement of plungers 40 when operatingsleeve 28 is released from the working position in which it is shown inFIG. 1.

The latch-means for the operating sleeve, to which the present inventionis particularly directed, includes a pair of arcuately shapedstop-levers 50, 52, each pivoted near its mid-point within similarlyshaped slots 54 and 56, respectively, in adjusting ring 34-. As bestseen in FIG. 7 slots 54 and 56 are formed on opposite sides of adjustingring 34 in a plane perpendicular to the longitudinal axis thereof. Pivotpins 58 for the stop-levers 59, 52 are located diametrically oppositeeach other such that they pass through the central portions of slots 54and 56 and are held firmly at their ends in passages 59 drilledlongitudinally in adjusting ring 34, into which they are press fit.Slots 54 and 56 are cut transversely through adjusting ring 34 to asuitable depth in order to leave oppositely disposed connecting portions60, 62 in the annular wall of adjusting ring 34. The ends of arcuateslots 54, 56 are defined by parallel chords disposed perpendicular to adiameter of the adjusting ring through pivot pins 58.

As best seen in FIG. 4, the outside diameter of stoplevers 50, 52 isapproximately equal to the CD. of adjusting ring 34 so that they can bepivoted to a position wholly within the periphery of the adjusting ring.In order to provide room within slots 54, 56 for stop-levers 50, 52 tomove between their latching positions shown in FIG. 3 and unlatchingpositions shown in FIG. 4, one end 52' of each stop-lever is madeslightly shorter than the other. In the latching position of FIG. 3, awedge-shaped segment on each of the opposite ends 50", 52 of stop-levers5t 52 projects outwardly of the peripheral surface of adjusting ring 34so that, as shown in FIG. 1, they engage the rear side of flange 32 ofthe operating sleeve 28, holding this member in its forward orchaser-closing position. When stop-levers 5t), 52 are pivoted clockwise,as viewed in FIGS. 2-4, to the unlatching position of FIG. 4, the ends56'', 52" are retracted within the periphery of adjusting ring 34permitting operating sleeve 28 to slide rearwardly to its chaseropeningposition. An outwardly directed flange 63 at the rear end of adjustingring 34 limits the rearward travel of operating sleeve 28 at a positionin which the walls 30 thereof clear the chaser holders 16 so that theymay be removed from the radial guide slots 14 for replacement.

The adjacent ends 56' and 52" as a pair, as well as ends 50" and 52 as asecond pair, of stop-levers 50 and 52 are interconnected by means ofidentical plungers 64 and 66, which are guided within passages 68 and70, respectively, through the connecting portions and 62 of adjustingring 34. Plungers 64, 66 are in substantially continuous engagement withthe opposite ends of stoplevers 5t), 52 so that any pivotal movement ofone causes a corresponding movement of the other. Plungers 64,

i 66 are each provided with an enlarged cylindrical headportion 72 and74, respectively, forming annular shoulders 76, 73 adjacent the smallerdiameter shanks 81 on which are fitted helical compression springs 82,84. The opposite ends of each of passages 68, 70 is reduced in diameterin order to accommodate and guide the shanks 80, 81 of plungers 64, 66and also to form an internal shoulder within each of passages 68 and 70against which one end of each compression spring 82, 84 is seated. Theopposite end of each compression spring engages one of the shoulders 76or 78 on each plunger.

As shown in FIGS. 3 and 4, the plungers 64 and 66 are arranged so as tourge stop-levers 50 and 52 in a counterclockwise direction toward theirlatching positions. It will be noted, however, that by pressing inwardlyeither on the end 5!)" of stop-lever 50 or on the end 52" of stop-lever52, both stop-levers will be pivoted simultaneously from their latchingpositions to their unlatching positions. Since in the presentconstruction the die-head is designed to have the chasers openedmanually, finger-cuts 86, 88 are formed in the rear part of theadjusting ring 34- adjacent the latching portions of the stoplevers attheir ends 50", 52". The finger-cuts 86, 88 provide better access to thestop-levers so that one or the other, or both, can be more readilydepressed by hand. In order to allow the operating sleeve 28 to be movedfrom its chaser-opening position, at which point its flange 32 isadjacent flange 63 on adjusting ring 34, it is necessary to depressstop-levers 50, 52 which, of course, snap outwardly when flange 32passes to the rear of adjusting ring 34'. To this end, the outer rearedge of each of the wedge-shaped latching portions of stop-levers 50 and52 is bevelled as shown at 90 and 92, respectively, in FIG. 1. Inaddition, the forward corner of flange 32 is also bevelled so that assleeve 28 is slid forward it will engage the bevelled surfaces ofstop-levers 50, 52 and will depress them until the flange 32 passes infront of them.

Adjusting ring 34 is provided in the usual manner with a tool socket 94to receive a suitable tool for turning it on shank 12 in adjusting thechasers to the desired thread size. A set-screw 96 is also provided forlocking the adjusting ring in place once the desired adjustment has beenmade.

Since the stop-levers in the present construction engage the operatingsleeve at diametrically opposite points, the operating sleeve is nottilted or cocked as it is being adjusted longitudinally of shank 12 bymeans of adjusting ring 34. In order to ensure this, however, it is ofcourse important that the two stop-lever slots 54 and 56 in theadjusting ring be accurately in line. While the same advantage could beobtained by using independently movable stop-levers located on oppositesides of the adjusting ring, this is not satisfactory because it isdiflicult to depress both levers simultaneously in order to release theoperating sleeve. The present invention, however, has solved thisproblem well and renders the use of two, or even more, stop-leverspractical.

What is claimed is:

1. In a die-head comprising a skeleton or frame having an elongatedshank, a plurality of chasers mounted on said skeleton for reciprocalmovement radially of the longitudinal axis of said shank into and out ofworkengaging position, an operating member supported on said skeletonfor movement longitudinally of said shank in one direction in order "tomove said chasers into workengaging position and in the other directionfor retracting said chasers, and stop-means positioned on said shank forlimiting the movement of said operating member in said other direction;the improvement in which said stopmeans comprises in combination aplurality of stop-levers each pivoted intermediate its extremities formovement into and out of latching position with respect to saidoperating member, means interconnecting adjacent ends of saidstop-levers such that each of said stop-levers is pivoted out oflatching position upon pivotal movement of any one of said stop-leversout of latching position, i

and resilient means urging said stop-levers into latching position.

2. The combination defined in claim 1, wherein said stop-means comprisesa pair of said stop-levers disposed diametrically opposite each other oneither side of said shank, the pivotal movement of said stop-leversbeing in a plane normal to the longitudinal axis of said shank.

3. In a die-head comprising a skeleton or frame having an elongatedshankpa plurality of chasers mounted on said skeleton for reciprocalmovement radially of the longitudinal axis of said shank into and out ofworkengaging position, an operating member supported on said skeletonfor movement longitudinally of said shank in one direction in order tomove said chasers into workengaging position and in the other directionfor retracting said chasers, and stop-means positioned on said shank forlimiting the movement of said operating member in said other direction;the improvement in which said stopmeans comprises in combination a pairof stop-levers disposed opposite each other on either side of saidshank, each stop-lever being pivoted intermediate its extremities formovement into and out of latching position with respect to saidoperating member, a pair of plungers interconnecting adjacent ends ofsaid stop-levers such that each of said stop-levers is pivoted out oflatching position upon pivotal movement or any one of said stop-leversout of latching position, and resilient means urging said stop-leversinto latching position.

4. In a die-head comprising a skeleton or frame having an elongatedshank, a plurality of chasers mounted on said skeleton for reciprocalmovement radially of the longitudinal axis of said shank into and out ofworkengaging position, an operating member supported on said skeletonfor movement longitudinally of said shank in one direction in order tomove said chasers into workengaging position and in the other directionfor retracting said chasers, and stop-means positioned on said shan forlimiting the movement of said operating member in said other direction;the improvement in which said stopmeans comprises in combination a pairof stop levers disposed opposite each other on either side of saidshank, each stop-lever being pivoted intermediate its extremities formovement into and out of latching position with respect to saidoperating member, means interconnecting adjacent ends of saidstop-levers comprising a first springloaded plunger having one endurging a first of said stoplevers in one direction about its pivot pointand the other end disposed for engagement with the second of saidstop-levers, a second spring-loaded plunger disposed between theopposite ends of said stop-levers and urging said second stop-lever intoengagement with said first plunger.

5. The combination defined in claim 4, wherein said stop-levers areidentical and said spring-loaded plungers are likewise identical.

6. The combination defined in claim 4, wherein each of saidspring-loaded plungers includes a compression spring urging one end ofthe plunger associated therewith against one of said stop-levers, theother end of each of said plungers extending in the opposite directioninto engagement with the other stop-lever.

7. The combination defined in claim 4, wherein said stop-means isdisposed in and supported by an adjusting ring threaded on the shank ofsaid skeleton tor adjustably positioning said stop-levers longitudinallyofsaid shank.

References Cited in the file of this patent UNITED STATES PATENTS1,683,126 .Breitens-tein Sept. 4, 1928 1,753,819 Breitenstein Apr. 8,1930 2,958,877 Strickland Nov. 8, 1960

1. IN A DIE-HEAD COMPRISING A SKELETON OR FRAME HAVING AN ELONGATEDSHANK, A PLURALITY OF CHASERS MOUNTED ON SAID SKELETON FOR RECIPROCALMOVEMENT RADIALLY OF THE LONGITUDINAL AXIS OF SAID SHANK INTO AND OUT OFWORKENGAGING POSITION, AN OPERATING MEMBER SUPPORTED ON SAID SKELETONFOR MOVEMENT LONGITUDINALLY OF SAID SHANK IN ONE DIRECTION IN ORDER TOMOVE SAID CHASERS INTO WORKENGAGING POSITION AND IN THE OTHER DIRECTIONFOR RETRACTING SAID CHASERS, AND STOP-MEANS POSITIONED ON SAID SHANK FORLIMITING THE MOVEMENT OF SAID OPERATING MEMBER IN SAID OTHER DIRECTION;THE IMPROVEMENT IN WHICH SAID STOPMEANS COMPRISES IN COMBINATION APLURALITY OF STOP-LEVERS EACH PIVOTED INTERMEDIATE ITS EXTREMITIES FORMOVEMENT INTO AND OUT OF LATCHING POSITION WITH RESPECT TO SAIDOPERATING MEMBER, MEANS INTERCONNECTING ADJACENT ENDS OF SAIDSTOP-LEVERS SUCH THAT EACH OF SAID STOP-LEVERS IS PIVOTED OUT OFLATCHING POSITION UPON PIVOTAL MOVEMENT OF ANY ONE OF SAID STOP-LEVERSOUT OF LATCHING POSITION, AND RESILIENT MEANS URGING SAID STOP-LEVERSINTO LATCHING POSITION.